Transmitting Data Using Stamps

Archiver

Hi, I'm currently in year 13 at Alleynes High School Staffs UK
studying electronics. For my project I have opted to design and
create a home burglar deterent system. For the three function module
units I have decided that it would be a good idea for them to be
wireless from the control unit.
To do this I have one transmitter in the control box and
three identical receivers in each of the module units. I am
investigating using a stamp to send out a signal and at the other end
decode it and switch the correct unit on. So basically I am sending a
code to all three receivers, but only want one of them to switch on -
the required one.
I was wondering if you could give me any information on how
to send a code and decode it at the other end using stamps.
Any information you could send me or directions to possibly
obtaining this
information would be greatfully received.


Many Thanks,
Jonathan Ayres

Archiver

I have been using stamps to transmit data to a robot for a couple of
years now. To perform the task that you are talking about is not
too difficult. All transceivers must be set to the same frequency
or channel. The main unit will transmit a command, which contains a
code indicating the unit the command is intended for. Each of the
sub units will receives the message validates the CRC and checks the
code to determine if it is for them. If it is then they will
transmit an acknowledgement (ACK) message back to the main unit, if
not they do nothing. If the master unit does not receive the
acknowledgement within a prescribed amount of time then it should
retry the transmission. The ACK message should contain a unit
verification ID so that the master unit is sure the correct sub unit
answered. The transmitted message can be as simple as a 1-byte code
followed by a CRC, and the ACK would return a 1-byte response code
and the original CRC value.

Parallax offers sample code for their transceivers. This code shows
how to setup a CRC and extract the message from the received
message.

Sanford Fusee



--- In basicstamps@y..., "ayreshire_84" <sheggzie@h...> wrote:
> Hi, I'm currently in year 13 at Alleynes High School Staffs UK
> studying electronics. For my project I have opted to design and
> create a home burglar deterent system. For the three function
module
> units I have decided that it would be a good idea for them to be
> wireless from the control unit.
> To do this I have one transmitter in the control box and
> three identical receivers in each of the module units. I am
> investigating using a stamp to send out a signal and at the other
end
> decode it and switch the correct unit on. So basically I am
sending a
> code to all three receivers, but only want one of them to switch
on -
> the required one.
> I was wondering if you could give me any information on how
> to send a code and decode it at the other end using stamps.
> Any information you could send me or directions to
possibly
> obtaining this
> information would be greatfully received.
>
>
> Many Thanks,
> Jonathan Ayres

Archiver

hi:
what you need is a ic made by holtek they are encoder and decoder
chips i have used them they work great and are easy to hook up
look on this web site www.laipac.com
get to products then the holtek button
they have many different types
one you can just encode a destintion
or you can send 8 bit of data thats encoded
the ones i use are 12-e [noparse][[/noparse]encoder] and 12-f [noparse][[/noparse]decoder]
they give me 256 different codes for my recivers with 16 chanels of
outputs per reciver
all they need is 1 resistor, input trigger, 8 pos dip sw [noparse][[/noparse]for addr],
and a 4 pos dip [noparse][[/noparse]for chanel] or a 4 pos hook up to the stamp
to select what unit to turn on
hope this helps
terry


--- In basicstamps@y..., "ayreshire_84" <sheggzie@h...> wrote:
> Hi, I'm currently in year 13 at Alleynes High School Staffs UK
> studying electronics. For my project I have opted to design and
> create a home burglar deterent system. For the three function
module
> units I have decided that it would be a good idea for them to be
> wireless from the control unit.
> To do this I have one transmitter in the control box and
> three identical receivers in each of the module units. I am
> investigating using a stamp to send out a signal and at the other
end
> decode it and switch the correct unit on. So basically I am sending
a
> code to all three receivers, but only want one of them to switch
on -
> the required one.
> I was wondering if you could give me any information on how
> to send a code and decode it at the other end using stamps.
> Any information you could send me or directions to
possibly
> obtaining this
> information would be greatfully received.
>
>
> Many Thanks,
> Jonathan Ayres